calldata-lint checks structured call-data JSON records (AI voice-agent call exports, telephony webhooks, CRM call logs) before they reach your systems. It verifies required fields (call_id, started_at, direction, from_number, to_number), field types, ISO-8601 timestamp validity and UTC normalization, E.164 phone-number format, negative/oversize duration checks, empty-transcript capture warnings, and HTTPS recording URLs. Supports extra required fields, --strict CI gating, --json output, and multiple files. Zero runtime dependencies — stdlib only (json, optparse, time).